High-Frequency Vibration Tests for Cement Concrete for Machine Tools (300–500 Hz)
High-Frequency Vibration Tests for Cement Concrete for Machine Tools (300–500 Hz)
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DOI：
10.1007/s42417-022-00475-2
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发表时间：
2022-04
影响因子：
2.7
通讯作者：
C. Brecher;C. Kiesewetter-Marko;M. Kalthoff;S. Neus
中科院分区：
文献类型：
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作者：
C. Brecher;C. Kiesewetter-Marko;M. Kalthoff;S. Neus
目的水泥混凝土有时用于机床行业，以降低成本和改善机床的动态性能。由于缺乏关于水泥混凝土在高频动载作用下材料性能的信息，基于WZL的共振原理研制了一台试验台。本文提出了试验台的进一步开发，以提高测试和结果评价的水平。此外，还描述了在高频范围内对超高性能混凝土(UHPC)进行交变载荷作用下的动态试验。试验的目的是研究频率范围和高压灭菌后处理对超高性能混凝土试件极限载荷的影响。方法为了能够对系统固有频率的变化做出原位反应，从而确保动态载荷的一致水平，开发了一种控制和调节方法，并将其应用到试验台中。此外，在试验台上对不同荷载水平和频率范围的超高性能混凝土试件进行了动态试验，也使用了自动试验规则。超高性能混凝土试件在生产后进行高压灭菌，以获得高材料性能并预期收缩变形。施加到试件上的载荷幅度被确定为先前确定的静态拉伸强度的函数。测试的载荷幅度设置在静态中心拉伸强度的37%到50%之间。测试频率分别约为326 GHz和475 GHz，因此处于高频范围内。结果首次使用新开发的自动测试规程进行测试表明，可以获得稳定的动态负载水平。对不同荷载水平和频率范围的高压蒸压超高性能混凝土试件的长期动态试验表明，超高性能混凝土在高频交变荷载作用下的极限荷载在静心抗拉强度的40%范围内。这些结果证实了其他研究人员对于较低频率范围的结论，并将结论扩展到所考察的频率范围。利用该试验装置和自动试验规则，疲劳试验的速度可比常规试验装置(参考频率约为10 GHz)快40~50倍。结论通过实现系统实际共振频率的自动适应，可以实现对试件的一致水平的动载荷。此外，可以说，超高性能混凝土在高频下交变作用力的极限荷载基本上不受实际高频范围或试件后续处理的影响。未来的研究应该更详细地定位极限力以及其他后处理，并转移到超高性能混凝土在机床实际部件中的应用。
PurposeOccasionally, cement concrete is used in the machine tool industry to reduce costs and improve the dynamic behavior of the machine. Due to a lack of information on the material behavior of cement concrete under dynamic loads with high frequencies, a test bench has been developed based on the principle of resonance at WZL. This paper presents the further development of the test bench to improve the testing and the evaluation of the results. Furthermore, the execution of dynamic tests with alternating loads in a high-frequency range of specimens of ultra-high-performance concrete (UHPC) is described. The aim of the described tests is to investigate the influence of frequency range and the autoclaving post treatment on the limiting load of UHPC specimens.MethodsTo be able to react in situ to a change in the natural frequency of the system and thus to ensure a consistent level of dynamic loading, a control and regulation method was developed and implemented into the test bench. Additionally, dynamic tests of UHPC specimens with different load levels and frequency ranges are executed on the test bench also using the automatic test regulation. The UHPC specimens were autoclaved after production to achieve high material properties and to anticipate shrinkage deformation. The amplitudes of load applied to the specimens were determined as function of the previously determined static tensile strength. The amplitudes of load tested were set between 37 and 50% of the static centric tensile strength. The frequencies tested were at about 326 Hz respectively 475 Hz and therefore lie in a high-frequency range.ResultsFirst tests with the new developed automatic test regulation show, that a consistent level of dynamic load can be achieved. The dynamic long-term tests of autoclaved UHPC specimens with different load levels and frequency ranges show, that the limiting load for alternating forces on UHPC in a high-frequency range lies in the area of 40% of the static centric tensile strength. These results confirm the conclusions of other researchers for the lower-frequency ranges and expand the conclusions to the examined frequency ranges. With the test set-up and the automatic test regulation, fatigue tests can be performed 40 to 50 times faster than with conventional test set-ups (with frequencies at about 10 Hz as a reference).ConclusionBy implementing an automatic adaption of the actual resonance frequency of the system, a consistent level of dynamic load on the specimens could be achieved. Furthermore, it can be stated, that the limiting load for alternating forces on UHPC at high frequencies is mostly unaffected by the actual range of high frequencies or the follow-up treatment of the specimens. Future research should issue a more detailed localization of the limiting force as well as other post-treatments and a transfer to the application of UHPC in real parts of machine tools.